Term
|
Definition
anaerobic
gram negative
no lipid A, but LPS+ (no endotoxin)
pleomorphic |
|
|
Term
| B. fragiles pathogenicity |
|
Definition
-polysaccharide capsule-->no phagocytosis, adhere to peritoneum
-fimbrae-->adhere to epi cells and fibrin, etc.; anti-phagocytic
-short chain FA from metabolism-->inhibit phagocytosis and intracellular killing
-beta-lactamase = resistant to penicillin and cephalosporin
-BFT enterotoxin: heat-labile zinc MMP
-rearrange F actin-->Cl- secretion and water--> diarrhea
-induce IL-8-->inflammation and injure epi cells |
|
|
Term
| B. fragiles Clinical Disease |
|
Definition
-gastroenteritis:
-see in kids <5y.o.
-due to BFT enterotoxin
-wound-related soft tissue infections
-pleuropulmonary, intraabdominal, genital infections
-usually causes disease BELOW diaphragm (so use metronidazole) |
|
|
Term
| B. fragiles diagnosis and treatment |
|
Definition
-To diagnose:
1. gram stain and colonization
2. grow on media supplemented with 20% bile (get black
precipitate)
3. resistant to kanamycin, vancomycin, colistin
Treat with:
-metronidazole
-carbapenems (imipenem)
-beta-lactam-beta-lactamase inhibitors: piperacillin-
tazobactam
-surgical intervention |
|
|
Term
|
Definition
-comma/S shaped, thin, small
-gram negative
-motile (flagellum)
-microaerophilic (decreased O2, increased CO2)
-LPS |
|
|
Term
| Campylobacter: pathogenicity |
|
Definition
-LPS = endotoxin; inactive when exposed to gastric acids
-C. fetus: S protein that prevents C3b binding (heat-stable and capsule-like)
-resistant to complement and Ab-mediated killing |
|
|
Term
| Campylobacter Clinical disease |
|
Definition
-zoonotic diseases:
-jejuni and coli in contaminated food (poultry)
-upsaliensis from dogs
-fecal-oral
-C. jejuni: damage to mucosal surfaces of jejunum (also ileum and colon)
-ulcerated, edematous, bloody mucosa and crypt abscess
in epithelial glands
-infiltration of laminal propria w/ neutrophils, etc.
-C. Jejuni and C. upsaliensis: Guillain-Barre b/c of antigenic cross-reactivity b/w neurons and LPS
-jejuni and upsaliensis: reactive arthritis and Reiter's syndrome
-C. fetus: septicemia, endocarditis, septic thromboplebitis, meningoencephalitis, abscesses
-immunocompromised and elderly
-jejuni, coli, upsaliensis: acute enteritis w/ diarrhea (watery-->bloody), fever, abdominal pain, bacteremia
-infections in spring and fall in infants, kids |
|
|
Term
| Campylobacter: diagnosis and treatment |
|
Definition
-jejuni grows at 42 degrees Celsius
-fetus grows at 37 degrees
-diarrhea = self-limiting
-if severe gastroenteritis give erythromycin or azithromycin
-proper food prep
-pasteurized milk |
|
|
Term
|
Definition
-gram negative rods
-microaerophilic (decreased O2, increased CO2)
-young culture = bacillary; older culture = coccoid
-flagella -->corkscrew motility |
|
|
Term
| Helicobacter: pathogenicity |
|
Definition
-LPS (O sidechain Antigen = Lewis blood group antigen =
protective)
-urease, catalase, oxidase positive
-initial colonization in stomach:
-local blocking of acid production by bacterial acid-
inhibitory protein
-neutralization of gastric acids by ammonia (urease)
-through gastric mucus, adhere to gastric epithelium
-urease activity-->byproducts: mucinase, phospholipase
vacuolating cytotoxin A (VacA)
-cytotoxin-associated gene (cagA) = virulence factor
injected into epi, interfere with cytoskeleton structure
-cagPAI induces IL-8 |
|
|
Term
| Helicobacter: Clinical Disease |
|
Definition
-lifelong colonization
-H. cinaedi and H. fennelliae colonize
-cause gastritis, bacteremia in immunocompromised
-Gastritis:
-acute: fullness, nausea, vomiting, hypochlorhydira
-chronic: confined to gastric antrum, PUD, gastric
adenocarcinoma, gastric MALT B-cell lymphoma
-decrease risk GERD, adenocarcinoma of lower esophagus
and gastric cardia |
|
|
Term
| Helicobacter: diagnosis and treatment |
|
Definition
Diagnose:
-microscopy
-urease breath test
-Antigen test with stool specimin
-microaerophilic culture incubation (slow growing)
-serology tells you if exposed
Treatment:
-proton pump inhibitor + macrolide + beta-lactam
-omeprazole + macrolide + beta-lactam |
|
|
Term
| Clostridium Difficile morphology |
|
Definition
-gram positive
-forms endospores (resistant to antibiotics)
-strict anaerobes |
|
|
Term
| C. difficile pathogenicity |
|
Definition
-toxins A and B = glucosyltransferases
-Enterotoxin = toxin A
-neutrophil chemotactic
-disrupt tight junctions-->increased permeability
-non blood diarrhea
-Cytotoxin = toxin B
-causes actin to depolymerize-->cytoskeleton destroyed
--> apoptosis
-Surface-layer protein (SLP)
-binding to intestinal epi-->local toxins-->tissue
damage
-Resistant to fluoroquinolones
-binary toxin = marker but don't know what is does to body |
|
|
Term
| C. difficile Clinical disease |
|
Definition
-normal intestinal flora in some healthy people
-intestinal flora esp in hospitalized patients
-pseudomembranous colitis: yellow-white plaques form after exogenous acquisition of it
-get from fecal-oral
-highly virulent strain with high mortality rate and increased relapse rate |
|
|
Term
| C. difficile diagnosis and treatment |
|
Definition
-detect enterotoxin (A) or cytotoxin (B) in feces
-discontinue the antibiotics that you were on (usually caused by broad spectrum antibiotic use)
-Metronidazole or vancomycin used in severe cases
-relapse occurs so do multiple rounds
-can't skill spores so relapse a lot |
|
|
Term
|
Definition
-gram negative
-facultative anaerobic rod
-oxidase negative
-fermenter |
|
|
Term
| E. coli groups and where cause disease |
|
Definition
-ETEC: small intestine
-EPEC: small intestine
-EAEC: small intestine
-EHEC: large intestine
-EIEC: large intestine |
|
|
Term
| E. coli ETEC pathogenicity and disease |
|
Definition
-Disease in small intestine
-fecal-oral route
-Adhesins: colonization factor antigens
-Enterotoxins: Heat-labile toxin and Heat-stable toxin
-plasmid-mediated toxins
-hypersecretion of fluids and electrolytes
-A-B toxin (B binds, A has ADP-ribosyltransferase
activity, interact with Gs-->increase cAMP-->Cl-
secretion, decreased Na and Cl absorption-->
watery diarrhea
-increase PG secretion
-Traveler's diarrhea: fecal-contaminated food/water
-no person-to-person
-watery diarrhea
-vomit, cramp, nausea
-low grade fever |
|
|
Term
| E. coli EPEC pathogenicity and disease |
|
Definition
-Disease in small intestine
-person-to-person spread
-Adhesins: bundle-forming pili, intimin
-Exotoxins: Enteroaggregative heat-stable toxin and Plasmid encoded toxin
-Pathogenesis
-bundle forming pili cause aggregation and microcolony
formation
-locus of enterocyte effacement pathogenicity island
mediates subsequent attachment to and destruction of
cell surface
-type III secretion to release translocated intimin receptor
which is R for outer membrane adhesin intimin
-intimin + translocated intimin R --> polymerize
actin-->lose cell surface integrity-->cell death
-watery diarrhea and vomiting
-nonblood stools
-Attachment/effacement histopathology: disrupt normal microvillus structure and get malabsorption and diarrhea |
|
|
Term
| E. coli EAEC pathogenicity and disease |
|
Definition
-Disease in small intestine
-Adhesin: Aggregative adherence fimbrae (like bundle-forming pili in EPEC)
-Exotoxins: Enteroaggregative heat stable toxin and Plasmid encoded toxin
-both cause increased fluid secretion
-Pathogenesis:
-plasmid-mediated aggregative adherence of rods =
stacked bricks
-adhere to epi-->stimulate mucus stimulation-->thick
biofilm formation
Disease:
-chronic diarrhea
-growth retardation in kids
-persistent watery diarrhea with vomiting, dehydration,
low-grade fever |
|
|
Term
| E. coli virulence factors |
|
Definition
-Encoded on:
-plasmids
-pathogenicity islands
-bacteriophage DNA |
|
|
Term
|
Definition
-most common gram-negative rod from patients with sepsis
-causes >80% community-acquired UTIs
-adhesins, hemolysin
-neonatal meningitis
-prominent cause of gastroenteritis in developing countries |
|
|
Term
| E. coli EHEC pathogenicity and disease |
|
Definition
-Disease in large intestine
-get from ingesting bacteria
-Adhesins: bundle-forming pili, intimin
-Exotoxins: Shiga toxins
-ingestion of less than 100 bacteria produces disease
-0157-H7 = most common serotype, evolved from EPEC
Pathogenesis
-attaching and effacing activity
-destroy intestinal microvilli-->descreased absorption
-Shiga toxin are A-B toxins
-disrupt protein synthesis
-Clinical Disease
-initially watery diarrhea-->grossly bloody diarrhia =
hemorrhagic colitis
-abdominal cramps
-no fever
-can progress to hemolytic uremic syndrome |
|
|
Term
| E. coli EIEC pathogenicity and disease |
|
Definition
-Disease in large intestine
-Adhesin: invasive plasmid antigen
-Exotoxin: hemolysin A
Pathogenicity
-pINV genes mediate bacterial invasion in colonic epithelium
-->lyse phagocytic vacuole-->cytoplasmic replication
-actin tail formation allows movement within cytoplasm and into adjacent epithelium (avoid immune response!)
Clinical Disease:
-fever, cramping, watery diarrhea
-can progress to dysentery with scant, bloody stool |
|
|
Term
| E. coli diagnosis and treatment |
|
Definition
-rapid growth on most media
-treat symptomatically unless disseminated disease occurs |
|
|
Term
|
Definition
-gram positive cocci
-in pairs and short chains
-anaerobic or aerobic
-catalase negative
-can't distinguish from S. pneumoniae in microscope
-cell wall with group-specific antigen (group D glycerol teichoic acid)
-E. faecalis, E. faecium
E. gallinarum, E. casseliflavus = most common colonizers of GI tract |
|
|
Term
| Enterococci pathogenicity |
|
Definition
-no potent toxin or virulence factor
-surface adhesin proteins for cell binding
-secrete proteins with:
-hemolytic activity (cytolysin)
-proteolytic activity (gelatinase, serine protease)
-engulfed, killed by phagocytes b/c no defense
-inherently resistant to some antibiotics:
-oxacillin, cephalosporins |
|
|
Term
| Enterococci Clinical disease |
|
Definition
-GI tract colonization
-common cause of nosocomial infection
-urinary tract, peritoneum, heart tissue infections
-severe complication = endocarditis
-get this after broad-spectrum antibiotic use
-polymicrobial infection in abdominal and wound infxns (see with other organisms) |
|
|
Term
| Enterococci diagnosis and treatment |
|
Definition
-colonize on nonselective media
-catalase negative
-PYR-positive (turns red)
-resistant to bile and optochin
-Treatment:
-synergistic combination of aminoglycoside and cell-
wall-active antibiotic (ampicillin, vancomycin)
-E. faecalis resistant to quinupristin/dalfopristin
-fluoroquinolones have poor activity against vanco-
resistant enterococci |
|
|
Term
|
Definition
-gram negative
-facultative anaerobic rods
-fermenter
-oxidase negative
-O antigen subdivides genus into subgroups
-S. enterica with the following serotypes:
-Salmonella Typhi
-Salmonella Choleracsuis
-Salmonella Typhimurium
-Salmonella Enteritidis
-Salmonella Typhi:
-intense staining on both ends |
|
|
Term
|
Definition
-fecal-oral-->attach to small intestine mucosa-->invade M cells and enterocytes-->replicate in endocytic vacuole (c/c with shigella?????)-->transported across cytoplasm-->release to blood, lymph
-pathogenicity island I: secrete invasion proteins
-pathogenicity island II: for bacterial evading immune response
-both have type III secretion system |
|
|
Term
| Salmonella Clinical disease |
|
Definition
-colonize most animals and humans
-Typhi and Paratyphi adapted to humans (don't cause disease in other hosts)
-chronic carriage in gall blader
-low infectious dose of Typhi->person-to-person spread
-kids <5y.o. and adults >60y.o. get most colonization
-summer and autumn months
-Sources:
-poultry, eggs, dairy products
-Types of infections:
-gastroenteritis: most common form in US
-nausea, vomit, nonbloody diarrhea, myalgia, headach
-septicemia: kids, elderly, immunocompromised
-enteric fever: from typhoid or paratyphoid fever
-through enterocytes, invade macrophages-->
replicate after get to liver, spleen, bone marrow-->
fever w/ headache, myalgias, anorexia
-reactive arthritis and Reiter's syndrome
-gallbladder colonization
-asymptomatic colonization of gall bladder = reservoir
for chronic colonization |
|
|
Term
| Salmonella Diagnosis and Treatment |
|
Definition
-isolate from stool specimens with selective media
-gas from glucose fermentation
-produces H2S
-do NOT give antibiotics for enteritis, may prolong disease
-Typhi vaccine for travelers to endemic areas |
|
|
Term
|
Definition
-gram negative rods
-non-lactose-fermenting
-cell wall O antigen divides genus into 4 groups
-4 species:
-S. dysenteriae
-S. boydii
-S. sonnei
-S. flexneri |
|
|
Term
|
Definition
-virulence plasmid carries structure genes; regulated by chromosomal genes
Pathogenesis:
-attach and invade M cells lining colon-->type III secretion so secrete 4 proteins into epithelial and macrophages (Ipa A, B, C, D)-->membrane ruffling-->bacteria engulfed-->phagocytic vacuole lysed--> bacteria replicate in cytoplasm (c/c w/ Salmonella!!????)-->actin filaments rearranged--> cell-to-cell passage and evade immune response-->cause apoptosis to avoid phagocytosis-->IL-1beta released--> attract PMN leukocytes-->destabilize intestinal wall integrity-->bacteria get deeper into epithelial cells
-Shiga toxin from S. dysenteriae: A-B exotoxin; inhibit protein synthesis |
|
|
Term
| Shigella Clinical disease |
|
Definition
-Humans are only reservoir
-S. sonnei in US
-S. flexneri in developing countries
-S. dysenteriae in Africa and Central America
-very LOW ID-50 (don't need many for infection) compared to Salmonella's high ID-50
-Shigellosis seen in pediatrics (<10y.o.)
-endemic in adult male homosexuals
-epidemics in daycares, nurseries
-person-to-person transmission via fecal-oral
-Clinical symptoms:
-first sign of infection: from enterotoxin in small
intestine, profuse watery diarrhea w/out evidence of
mucosal invasion
-as proceed, lower abdominal cramps and tenesmus
with pus and blood in stool
-neutrophils, RBCs, mucus w/in stool
-Reactive arthritis and Reiter's syndrome associated
Transmission:
-fingers, flies, food, feces |
|
|
Term
| Shigella diagnosis and treatment |
|
Definition
-isolate from stool sample w/ selective media
-treatment: antibiotics to shorten course of symptomatic disease and fecal shedding (in vitro susceptibility tests) |
|
|
Term
|
Definition
Reservoir: Shigella and Salmonella Typhi in humans. Non-typhi salmonella in animals
ID50: high in Salmonella. Low in Shigella.
Diarrhea as prominent feature: In shigella and non-typhi salmonella. Not prominent in Typhi (have fever)
Bloodstream invasion: Yes in salmonella; no in shigella
Chronic carrier state: Yes for Typhi salmonella; no for Shigella
Lactose fermentation: no for shigella and salmonella
H2S production: yes for salmonella; no for shigella
Vaccine available: only for typhi salmonella. |
|
|
Term
| Vibrio parahaemolyticus and vulnificus morphology |
|
Definition
-gram negative curved rods
-polar flagella
-facultative anaerobic
-fermentative
-pili = virulence factor |
|
|
Term
| V. parahaemolyticus pathogenicity |
|
Definition
-Kanagawa hemolysin = thermostable direct hemolysin
-virulent strain = Kanagawa positive
-enterotoxin-->gastroenteritis
-induced chloride ion secretion (watery diarrhea)
-LPS: lipid A, core polysaccharide, O polysaccharide |
|
|
Term
| V. parahaemolyticus Clinical disease |
|
Definition
-gastroenteritis
-wound infection, bacteremia
-most common cause of bacterial gastroenteritis in japan, SE Asia
-most common gastroenteritis species in US
-ingest raw seafood-->explosive watery diarrhea
-no gross evidence of blood or mucus
-abdominal cramps, nausea, headache, vomiting, low-grade fever
-uneventful recovery in about 72 hours |
|
|
Term
| V. parahaemolyticus diagnosis and treatment |
|
Definition
-culture early in disease at neutral or alkaline pH
-require salt for growth; killed by acidic pH in stomach
-Kanagaway hemolysin-->beta-hemolytic on agar media with human blood
-poor survivval in acidic or dry environment
-antibiotics can shorten length; self-limiting though
-no vaccine available (have one for vibrio cholera) |
|
|
Term
| V. vulnificus pathogenicity |
|
Definition
-acidic polysaccharide capsule-->antiphagocytic, important for dissemination of infection
-cytolysins, proteases, collagenases-->tissue destruction |
|
|
Term
| V. vulnificus Clinical disease |
|
Definition
-bacteremia and wound infections
-eat raw oyster-->primary septicemia (sudden onset fever and chills, vomiting, diarrhea, abdominal pain)-->secondary skin lesions with tissue necrosis
-wound infection from swimming in seawater-->swelling, erythema, pain at wound site-->vesicles or bullae--> tissue necrosis
-worse infection in immunocompromised, in chronic renal failure, hematopoietic or hepatic disease
-highly fatal outcomes |
|
|
Term
| V. vulnificus diagnosis and treatment |
|
Definition
-not usually cultured (die!)
-can culture wounds or blood
-die in acidic or dry environment
-need salt for growth
-minocycline + fluoroquinolone or cefataxime
-no vaccine available (vaccine available for vibrio cholera) |
|
|
Term
| Yersinia Enterocolitica morphology |
|
Definition
-gram negative rods
-facultatively anaerobic
-fermenter
-oxidase negative |
|
|
Term
| Yersinia Enterocolitica pathogenicity |
|
Definition
-type III secretion-->secrete YopH, YopE, YopJ/P gene products:
-YopH: dephosphorylates proteins required for
phagocytosis
-YopE: disrupt actin filaments-->cytotoxic
-YopJ/P: initiate apoptosis in macrophages
-also suppress cytokines |
|
|
Term
| Yersinia Enterocolitica Clinical disease |
|
Definition
-zoonotic disease: humans = accidental host
-pigs, rodents, livestock, rabbits
-enterocolitis in Scandanavia, colder US areas
-infections in cold months
-Serotype O8 associated w/ disease in US
-Gastroenteritis:
-can't distinguish clinically from Shigella or Salmonella
-ingest contaminated food products or water
-diarrhea, fever, abd pain
-acute lasts 1-2 weeks
-chronic can last months
-involves terminal ileum: can mimic acute appendicitis
-mesenteric nodes enlarged=mesenteric adenitis
-can case blood transfusion-related bacteremia and
endotoxic shock
-related to reactive arthritis and Reiter's syndrome |
|
|
Term
| Yersinia Enterocolitica diagnosis and treatment |
|
Definition
-colonize at 4 degrees celsius for a while
-so can colonize refrigerated food or blood products
-self-limited gastroenteritis
-susceptible to broad-spec antibiotics |
|
|
Term
| Anaerobic bacteria of colon that cause abscess due to bowel perforation |
|
Definition
B. fragillis
clostridia
peptostreptococci
Rx with metronidazole |
|
|
Term
|
Definition
-sterile at birth
-newborns in ICU colonized with: Enterobacteriacaea (klebsiella, citrobacter, enterobacter)
-breast fed babies: lactic acid strep and lactobacilli and Ig
-bottle-fed babies: less prominent lactobacilli
-flora changes w/ food changes as age |
|
|
Term
| peritonitis stage associated with |
|
Definition
E. coli and other facultative anaerobes
-acute pain |
|
|
Term
| abscess formation associated with |
|
Definition
| B. fragilis and other obligate anaerobes |
|
|
